Liquid sampling apparatus



United States Patent 3,201,995 LIQUID SAMPLING APPARATUS Ray E. Griffith, Cleveland, and Richard E. Kessler, Rocky River, Ohio, assignors to The Standard Oil Company, Cleveland, (lhio, a corporation of Ohio Filed May 17, 1962, Ser. No. 195,503 2 Claims. (Cl. 73-422) The present invention relates to automatic liquid sampling apparatus which is adapted to obtain a composite sample of liquids of variable composition. The apparatus of this invention is particularly suitable for the collection of composite samples of liquefied petroleum gas as it is being transported in a pipeline from one place to another.

Liquefied petroleum. gas (also referred to as L.P.G.) comprises normally gaseous hydrocarbons such as propane and butane which are maintained in their liquid state by proper adjustment of temperature and pressure. Such gases are a commercially important by-product of the petroleum refining industry and they are widely used,

e.g., they may be transported in portable containers to supply fuel to areas which are not served by natural gas transmission lines.

One of the characteristics of liquefied petroleum gases is that they ordinarily do not have a fixed composition. Their composition varies at the point of manufacture due to the constantly changing nature of the refining operations from which they result. Accordingly, in sampling such gases it is usually necessary to obtain a composite sample of the gas rather than a spot sample, since the composite sample will reflect variations in the composition of the gas as it is manufactured.

It is, therefore, one object of this invention to provide an apparatus which will collect a composite sample of liquid during a pre-determined period of time.

Another object of this invention is to provide an apparatus to collect a composite sample of a flowing stream of liquid having a variable composition.

It is another object of this invention to provide an automatic liquid sampling apparatus.

Still another object of this invention is to provide an apparatus for the sampling of liquefied petroleum gas which incorporates safety features designed to prevent the escape of such gases from the apparatus.

In brief, the sampling apparatus of this invention comprises a sample bomb, a liquid receiver, a solenoid valve adapted to control the flow of liquid between the sample bomb and the receiver, and a timer which regulates the operation of the solenoid valve. The apparatus also includes a pressure switch which is adapted to override the timer and close the solenoid valve in response to a rise in pressure within the receiver.

The attached patent drawing shows a schematic diagram of the sampling apparatus of this invention. Conventional equipment such as strainers and couplings are not shown on the drawing since they form no part of the present invention.

The sample bomb which is employed in the present invention is portable and it is otherwise conventional. In cases where the apparatus is employed for the sampling of liquefied petroleum gas, it is understood that the sample bomb will be of a type designed to withstand high pressures.

, The timer is also conventional and it may be a simple clock, mechanism which may be driven either electrically or by spring means.

The receiver must have a volumetric capacity at least as great as the volumetric capacity of the sample bomb. Preferably, it is constructed of a transparent material such as glass or plastic and it may be graduated so that the "ice amount of liquid contained therein may be ascertained by visual observation.

Valves employed in the apparatus of this invention may be of any conventional type, although it may be desirable to use needle valves in order to achieve precise control in the system.

Referring now specifically to the drawing, the main stream of liquid of which a periodic sample is desired flows through a main conduit 10. Communicating with the conduit 10 is sample conduit 11 which is relatively smaller than conduit 10. A by-pass conduit 12 equipped with valve means 13 communicates with conduits 11 and 10. Proceeding down conduit 11, valve means 14 are disposed in conduit 11 below the juncture of conduits 11 and 12. Conduit 11 communicates with a portable sample bomb 15. Following sample bomb 15, valve means 16 are disposed within conduit 11.

The principal control element in the circuit is the solenoid valve 17 which is disposed within conduit 11 following valve 16. Valve 17 is operatively connected with a timer 18 and pressure switch 19. Conduit 11 communicates at its lower terminus with a receiver 20 which is vented to the atmosphere by means of conduit 21. An orifice plate 25 is disposed within conduit 21. Pressure switch 19 communicates with the vent line 21 by means of conduit 22 and switch 19 is operatively associated with valve 17. The receiver 20 also communicates with conduit 23 equipped with valve means 24 and this arrangement provides a drain line for receiver 20.

In operation, the apparatus of this invention operates in accordance with the following description. The sample bomb 15 is initially filled with a liquid which is incompatible with the liquid to be sampled. In the case of liquefied petroleum gas, a liquid such as brine may be employed since both the hydrocarbons and minor impurities such as hydrogen sulfide and carbonyl sulfide are relatively insoluble in it. Valves 14 and 16 are open while valve 13 in by-pass line 12 is closed. The timer 18 causes valve 17 to periodically open according to a pre-determined schedule, and during the intervals when valve 17 is open liquid from conduit 10 will displace a part of the liquid in bomb 15 and force it into receiver 20. When all of the displacement liquid has been transferred to the receiver, valve 13 is opened and the valves 14 and 16 are closed in order to permit the removal of sample bomb 15. The receiver 20 may then be drained by opening valve 24.

In the case where liquefied petroelum gas is being sampled, a malfunction of timer 18 or the inadvertence of an operator may result in some of the liquefied gas being transferred to receiver 20. Since receiver 20 is vented to the atmosphere the liquefied gas will vaporize but orifice plate 25 will prevent its rapid escape from receiver 20 and this will result in an increase in the pressure Within receiver 20 which, in turn, will actuate switch 19. Switch 1% will close valve 17 and it will remain closed until it is manually reset. In this manner, the escape of flammable gases from the apparatus to the atmosphere is effectively precluded.

Various modifications of the apparatus described herein may be employed without departing from the spirit or scope of this invention and this application for Letters Patent is intended to cover all such modifications as would reasonably fall within the scope of the appended claims.

We claim:

1. A liquid sampling apparatus comprising a sample bomb including means for receiving a sample therein, a receiver having input and output ends, conduit means connecting said sample bomb and said receiver input end, valve means associated with said conduit means so as to control liquid flow therein, timer means operatively associated with said valve means whereby said valve means may be automatically opened and closed in accordance with a pre-determined schedule, a slow leaking vent line;

open to the atmosphere; connected to the receiver output end, maintaining limited pressure in the receiver; and pressure sensitive switch means connected to said receiver output end and adapted to close said valve means in response to a pressure rise within said receiver;

2. A liquid sampling apparatus comprising a sample 7 bomb including means for' receiving a sample therein, a transparent graduated receiver,"conduit means connecting said sample bomb and said receiver, valve means asvalve means whereby s'aid tvalve means may be automatically opened and'closed in accordance with a predetermined scheduled, and pressure sensitive switch means associated withsaid r'eceiver and a'da'pted to override said sociated with said conduit means soas to control liquid I flow therein, timer meansoperatively,associated with said timer means and close said valve means in response to a pressure rise within said receiver and retain it closed independent of subsequent pressure variations.

References Cited bythe Examiner UNITED STATES" PATENTS 52,057,889. 10/36 ,Fagan 141-39 "2,245,679 6/41; Kelley 73-4215 2,489,394-11/49 Austin 73-4215 9/52 Breedlove t a1. 73 422 FOREIGN PATENTS V 

1. A LIQUID SAMPLING APPARATUS COMPRISING A SAMPLE BOMB INCLUDING MEANS FOR RECEIVING A SAMPLE THEREIN, A RECEIVER HAVING INPUT AND OUTPUT ENDS, CONDUIT MEANS CONNECTING SAID SAMPLE BOMB AND SAID RECEIVER INPUT END, VALVE MEANS ASSOCIATED WITH SAID CONDUIT MEANS SO AS TO CONTROL LIQUID FLOW THEREIN, TIMER MEANS OPERATIVELY ASSOCIATED WITH SAID VALVE MEANS WHEREBY SAID VALVE MEANS MAY BE AUTOMATICALLY OPENED AND CLOSED IN ACCORDANCE WITH A PRE-DETERMINED SCHEDULE, A SLOW LEAKING VENT LINE, OPEN TO THE ATMOSPHERE, CONNECTED TO THE RECEIVER OUTPUT END, MAINTAINING LIMITED PRESSURE IN THE RECEIVER, AND PRESSURE SENSITIVE SWITCH MEANS CONNECTED TO SAID RECEIVER OUTPUT END AND ADAPTED TO CLOSE SAID VALVE MEANS IN RESPONSE TO A PRESSURE RISE WITHIN SAID RECEIVER. 